| 1 | import json |
| 2 | |
| 1 | 3 | class RestAPI: |
| 2 | 4 | def __init__(self, database: dict | None = None): |
| 3 | | pass |
| 4 | | |
| 5 | # Initialize the in-memory database |
| 6 | self.database = database if database is not None else {"users": []} |
| 7 | |
| 5 | 8 | def get(self, url: str, payload: str | None = None) -> str: |
| 6 | | pass |
| 7 | | |
| 9 | # Edge Case: Handle invalid URL |
| 10 | if url != "/users": |
| 11 | return json.dumps({"error": "Invalid URL"}) |
| 12 | |
| 13 | # Edge Case: Handle empty database |
| 14 | if not self.database["users"]: |
| 15 | return json.dumps({"users": []}) |
| 16 | |
| 17 | # Parse payload if provided |
| 18 | if payload: |
| 19 | try: |
| 20 | data = json.loads(payload) |
| 21 | # Edge Case: Handle missing 'users' key in payload |
| 22 | if "users" not in data: |
| 23 | return json.dumps({"error": "Invalid payload"}) |
| 24 | |
| 25 | # Filter users based on payload |
| 26 | requested_users = data["users"] |
| 27 | users = [user for user in self.database["users"] if user["name"] in requested_users] |
| 28 | # Sort users by name |
| 29 | users.sort(key=lambda x: x["name"]) |
| 30 | return json.dumps({"users": users}) |
| 31 | except json.JSONDecodeError: |
| 32 | # Edge Case: Handle invalid JSON in payload |
| 33 | return json.dumps({"error": "Invalid JSON payload"}) |
| 34 | else: |
| 35 | # Return all users sorted by name |
| 36 | users = sorted(self.database["users"], key=lambda x: x["name"]) |
| 37 | return json.dumps({"users": users}) |
| 38 | |
| 8 | 39 | def post(self, url: str, payload: str | None = None) -> str: |
| 9 | | pass |
| 40 | # Edge Case: Handle invalid URL |
| 41 | if url not in ["/add", "/iou"]: |
| 42 | return json.dumps({"error": "Invalid URL"}) |
| 43 | |
| 44 | # Edge Case: Handle missing payload |
| 45 | if not payload: |
| 46 | return json.dumps({"error": "Payload required"}) |
| 47 | |
| 48 | try: |
| 49 | data = json.loads(payload) |
| 50 | except json.JSONDecodeError: |
| 51 | # Edge Case: Handle invalid JSON in payload |
| 52 | return json.dumps({"error": "Invalid JSON payload"}) |
| 53 | |
| 54 | if url == "/add": |
| 55 | # Edge Case: Handle missing 'user' key in payload |
| 56 | if "user" not in data: |
| 57 | return json.dumps({"error": "Missing user field"}) |
| 58 | |
| 59 | user_name = data["user"] |
| 60 | |
| 61 | # Edge Case: Handle non-string user name |
| 62 | if not isinstance(user_name, str): |
| 63 | return json.dumps({"error": "User name must be a string"}) |
| 64 | |
| 65 | # Edge Case: Handle duplicate user |
| 66 | for user in self.database["users"]: |
| 67 | if user["name"] == user_name: |
| 68 | return json.dumps({"error": "User already exists"}) |
| 69 | |
| 70 | # Create new user |
| 71 | new_user = { |
| 72 | "name": user_name, |
| 73 | "owes": {}, |
| 74 | "owed_by": {}, |
| 75 | "balance": 0.0 |
| 76 | } |
| 77 | self.database["users"].append(new_user) |
| 78 | return json.dumps(new_user) |
| 79 | |
| 80 | elif url == "/iou": |
| 81 | # Edge Case: Handle missing required fields |
| 82 | required_fields = ["lender", "borrower", "amount"] |
| 83 | for field in required_fields: |
| 84 | if field not in data: |
| 85 | return json.dumps({"error": f"Missing {field} field"}) |
| 86 | |
| 87 | lender_name = data["lender"] |
| 88 | borrower_name = data["borrower"] |
| 89 | amount = data["amount"] |
| 90 | |
| 91 | # Edge Case: Handle non-string lender or borrower |
| 92 | if not isinstance(lender_name, str) or not isinstance(borrower_name, str): |
| 93 | return json.dumps({"error": "Lender and borrower must be strings"}) |
| 94 | |
| 95 | # Edge Case: Handle non-numeric amount |
| 96 | if not isinstance(amount, (int, float)): |
| 97 | return json.dumps({"error": "Amount must be a number"}) |
| 98 | |
| 99 | # Edge Case: Handle negative amount |
| 100 | if amount < 0: |
| 101 | return json.dumps({"error": "Amount must be positive"}) |
| 102 | |
| 103 | # Edge Case: Handle lender and borrower being the same person |
| 104 | if lender_name == borrower_name: |
| 105 | return json.dumps({"error": "Lender and borrower cannot be the same person"}) |
| 106 | |
| 107 | # Find lender and borrower in database |
| 108 | lender = None |
| 109 | borrower = None |
| 110 | for user in self.database["users"]: |
| 111 | if user["name"] == lender_name: |
| 112 | lender = user |
| 113 | elif user["name"] == borrower_name: |
| 114 | borrower = user |
| 115 | |
| 116 | # Edge Case: Handle lender or borrower not found |
| 117 | if lender is None or borrower is None: |
| 118 | return json.dumps({"error": "Lender or borrower not found"}) |
| 119 | |
| 120 | # Update lender's owed_by |
| 121 | if borrower_name in lender["owed_by"]: |
| 122 | lender["owed_by"][borrower_name] += amount |
| 123 | else: |
| 124 | lender["owed_by"][borrower_name] = amount |
| 125 | |
| 126 | # Update borrower's owes |
| 127 | if lender_name in borrower["owes"]: |
| 128 | borrower["owes"][lender_name] += amount |
| 129 | else: |
| 130 | borrower["owes"][lender_name] = amount |
| 131 | |
| 132 | # Update balances |
| 133 | lender["balance"] += amount |
| 134 | borrower["balance"] -= amount |
| 135 | |
| 136 | # Return updated users sorted by name |
| 137 | users = sorted([lender, borrower], key=lambda x: x["name"]) |
| 138 | return json.dumps({"users": users}) |
| 139 | # Handled Edge Cases: Invalid URL, empty database, missing 'users' key in payload, invalid JSON in payload, missing payload, missing 'user' key in payload, non-string user name, duplicate user, missing required fields, non-string lender or borrower, non-numeric amount, negative amount, lender and borrower being the same person, lender or borrower not found |